


Crouching Doctor, Hidden Basilisk

by mundungus42



Category: Doctor Who, Harry Potter - J. K. Rowling
Genre: Alternate Universe - Doctor Who Fusion, Alternate Universe - Harry Potter Setting, Crossover, David Tennant Roles, Gen, Humor, Meta
Language: English
Status: Completed
Published: 2012-03-07
Updated: 2012-03-07
Packaged: 2017-11-01 15:01:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,739
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/358164
Author URL: https://archiveofourown.org/users/mundungus42/pseuds/mundungus42
Summary: <blockquote class="userstuff">
              <p>Martha Jones has some issues with "Harry Potter and the Deathly Hallows." Thankfully, she and the Doctor are in a position to do something about it.</p>
            </blockquote>





	Crouching Doctor, Hidden Basilisk

Another day, another dunderhead to save from his own idiocy. Headmaster Snape consulted the diary that he had enchanted to predict, based on past incidents, what student or students would be involved in today's mischief, and was surprised to find Harry Potter's name. He snorted loudly. This was exactly the time of year that Potter would usually do something incredibly stupid, but he was off gallivanting in places unknown in search of the Dark Lord's three remaining Horcruxes. Despite the air of oppression and despair that hung over the student body, Severus was looking forward to his first Potter-free end of term in six years.

He took the diary's predictions with a very large grain of salt. For example, it had failed to predict that Ginny Weasley would scrawl anti-Death Eater graffiti near the Carrows' classrooms yesterday. Fortunately, he had caught her and not the Carrows, who would have beaten the girl senseless in front of the entire school. Instead, Severus had ordered her to clean the floor of the Great Hall without magic during breakfast. It was a good punishment. It was humiliating enough to satisfy the Carrows, since they knew that the Slytherins, bless their black hearts, would undoubtedly use the opportunity to drop or spill everything they could get their hands on, yet it was also the sort of punishment that would feed revolutionary spirit, rather than break it.

Still, his diary had correctly predicted something from Luna Lovegood in the Great Hall the day she decided to break into a song she'd written called "Voldemort's Privates." Her melodic speculations were so profane and so bizarre that even Amycus waited until the song was finished to cuff her across the ear and drag her off to the punishment chamber. Though it was far from perfect, the predictive diary was still highly useful for interceding on the young idiots' behalf. Severus sipped his morning tea and tried to envision what sort of madness the day would bring.

Despite Severus Snape's formidable and morbid imagination, he sorely underestimated what was to come. He began to appreciate this fact when an eerie mechanical whine pierced the silence of his office. A wind began to blow, and a shadowy form began to take shape. Severus did the sensible thing and ducked under his desk, pulling the visitor's chair up to the desk so that it hid his presence.

It was odd. One moment the area next the door contained carpet and empty air. The next moment the space was filled with a blue police box. Severus blinked. It was an unusual thing to happen, certainly, but by no means unprecedentedly so.

Seeing a young woman dressed in Muggle clothing step out of the police box was also strange, but again, nothing beyond the pale. She appeared to be in her early twenties and was uncommonly pretty, with creamy brown skin and intelligent eyes.

She was looking around the room with an expression of wonder on her face. "Doctor?" she called. "I think you made a wrong turn."

"Impossible,"' protested a male voice from within. "We're exactly where I meant us to – oh, hello," he said, sticking his head through the door frame. Unfortunately, his face was obscured by the girl.

"I know this place," she said, a tremor in her voice.

"Do you think so?" he asked doubtfully, crossing out of Severus's range of vision, save for his feet, which were shod in white trainers that were somewhat incongruous with his pinstriped trousers.

"Look at the paintings move!" she exclaimed, walking to the other side of the box. "Armando Dippet!" she exclaimed. "Phineas Nigellus Black! Do you know what this means, Doctor?" she exclaimed.

"It means we've accidentally landed in 2010 at the new theme park in Orlando. We'd better go before any of the cast members catch us and throw us out. Come along, Martha, you don't want to spoil yourself for book seven, now do you?"

"Theme park!" sputtered Black. "I'll have you know, young man-"

"Bollocks to that," said Martha. "I want to look around. I want to see Fawkes. Huh, they forgot the sherbet lemons on his desk. That's a bit rubbish, isn't it?"

The man, or doctor, had circled the police box and stepped into Severus's narrow range of vision. At the sight of his face, Severus's blood ran cold. Even for a man who had seen as much as he had, the sight of a man who had been kissed by Dementors and died of pneumonia the following winter appearing from inside a blue box that had materialized in his office was decidedly unusual.

"Martha," he said seriously, looking at her from underneath an absurdly gelled coiffure, "We really shouldn't be here."

The girl turned to face him. "But why?" she demanded. "If my sister finds out I had the chance to look around and didn't, she'll kill me. Especially if it tells me anything about the last book."

The man called the Doctor gave a great sigh. "This place isn't safe for you," he said seriously.

Martha clapped her hands over her mouth to muffle her shriek. "You mean it's real? We really are here?"

"Yes," he said. "But you're not to tell anyone."

"I can't believe it!" squealed the girl. "When are we?"

Snape curled himself into a tighter ball. Of course they were time travelers. There were powerful wards protecting the school from people popping in and out from one physical location to another, but there seemed to be a distinct lack of protection from time manipulation. Severus made a note to look into that particular loophole post-haste.

"Difficult to say, really," the man replied, stepping forward to the desk. "Oh. Oh dear."

"What is it?" she said, joining him at the desk. "Oh."

Severus realized that they must be looking at Albus's portrait, but he was more interested by the fact that both of them were standing directly in front of his hiding place. He aimed his wand and cast a nonverbal spell at their feet. The girl cried out in alarm as the silvery ropes wrapped around her and tied her tight. Barty Crouch Jr., for that was unmistakably who the ersatz doctor was, burst out laughing. Severus could see their legs, firmly lashed together, begin to lean.

"Doctor, I'm going to-"

"Hold on, Martha, just-"

Both statements ended in a simultaneous "OOF" as they both landed on their backs on the floor in front of Severus's desk.

Barty seemed unfazed. "Tidy bit of work, don't you think, Martha?" he called gaily.

"Ow! Is that what you call it?" she asked peevishly.

"Quite tidy. Quality rope, good, solid knots. All the more impressive when you consider the spell was cast silently. I think we may have a master in our midst. Well, let's see who you are, then."

Severus rose from his hiding place, wand at the ready, and stepped around his desk.

The girl gave a gasp, but Barty grinned up at him. "Brilliant. Headmaster Snape, I presume?"

"Oh my God!" whispered Martha. "I can't believe it's him! He's my absolute favorite!"

Clearly the girl had knocked her head when she fell. Severus ignored her. "No games this time, Barty. Why are you here?"

Barty's eyebrows drew together. "Who's Barty?"

"Barty Crouch. A man who died without a soul," said Severus.

"You mean the bloke who sent all those people to Azkaban without trial?" asked the girl.

"His son," said Severus, looking at Martha with renewed interest. She wasn't a witch, was she?

"Of course," said Martha. "I knew he'd had the Dementor's kiss, so I guess it's not surprising he's dead now."

Barty shot her a surprised look. "How'd you know all that?"

"I read, don't I?" she replied pertly.

"Quiet," ordered Snape. "Do you expect me to believe that you are not Barty Crouch Jr., despite being identical in face and body?"

"Yup," he replied brightly. "And I'm no wizard. I'm the Doctor."

"What are you doing in my office?"

"Would you believe we took a wrong turn?" he asked.

"No. And while you're at it, I should love to hear your explanation for these books you keep talking about."

"Actually, so would I," said Martha. "I'd be very interested to know how I came to be standing in the middle of one."

"Ah, but you're lying down now," said the Doctor. "And we don't actually know that we're in the middle. What's the last thing Harry Potter was in the news for?"

"You will answer me," ordered Severus in a dangerous voice. "Tell me about the books."

The Doctor's eyes flickered to the side, which made Severus suspect that the next words out of his mouth would be an outrageous lie.

"They're history books," said the Doctor at last. "I think you've figured out that we're time travelers. We know your future, which is why we need to be going before we ruin your timeline or create any paradoxes. Now, if you could just untie us, we'll get back in my big blue time machine and be on our way."

"And book seven?"

"It's the last book in the series," said Martha. "And I haven't read it yet, so if you want to know anything that happens after, well, what happened up on the tower, you'll have to ask him."

"I won't need to ask at all," said Severus, giving them what he knew would be a ghoulish smile. "Legilimens!"

"Really, Severus," said a voice in his head. "It's manners to say please. I can call you Severus, right?"

Severus released the spell. "What in blazes?"

"That's fantastic," said the Doctor. "Did you know that Occlumency completely eliminates the need to touch?"

"You are no Muggle," said Severus frowning.

"He's not magic, he's just not human," piped up Martha. "Go on, Doctor. Show him."

"All right?" asked the Doctor, looking up at Severus seriously.

Severus nodded and cast the spell once more. His mind was flooded with images of stars and supernovas, of a beautiful planet the Doctor and his kind had called home. There were evil robots shaped like pepper pots, potato-headed warriors, and terrifying tentacled faces. He saw the destruction of worlds and the deaths of millions, but also a parade of human faces, and he felt the Doctor's love and respect for humans and their never-ceasing march toward freedom and yearning for peace. He understood the Doctor's need to change things for the better when possible and ease the burden when it wasn't.

As Severus ended the spell, an entire world of possibility opened up to him. A telekinetic extraterrestrial being with knowledge of the future and a penchant for saving the world could be a potent ally against the Dark Lord. However, Severus understood the rules of time travel as well as any educated wizard, and knew that the Doctor would resist doing anything that changed history as he knew it.

"I see," said Severus, sitting at his desk. He waved his wand lazily and a second guest chair appeared.

"Wicked," said Martha appreciatively. He was about to release them both from their bonds when they both stood, and the ropes fell away from them.

He raised an eyebrow at the Doctor, who held up a device that looked halfway between a blue torch and spanner. "Sorry."

Severus gestured for them to take their seats. Once they had done so, his gaze traveled from one to the other.

"The fact that both of you seem to think well of me leads me to believe that my role as a spy eventually comes to light."

"I figured as much from the 'Severus, please' moment," said Martha. "Oh, sorry," she said at Severus's flinch. "I guess it's still a bit raw."

"You're right," said the Doctor to Severus. "Your role is known, but I really can't divulge anything that might change the way things turn out."

"I can't imagine you would expect me to ask that of you unless my demise is imminent."

"She can't!" exclaimed Martha angrily. "I mean, that can't be! You're the most interesting cha-,I mean, person in this whole timeline."

"It's all right," said Severus, who was unaccountably pleased at her outrage on his behalf. "I've come to terms with the fact that I'm unlikely to survive this, especially if Potter is to succeed."

"Doctor," said Martha, "we've got to do something. Surely there's something we can do."

"Martha," said the Doctor,"I'm sorry. But there's nothing we can do. The book is explicit. Severus dies. Heroically, tragically, but also quite clearly."

"He's a potions master!" she exclaimed. "He can bottle fame, brew glory, and put a bloody stopper in death! Surely he can fake it well enough to fool everybody!"

Severus could see the Doctor about to refuse and raised his hand to forestall him. "It's no use," he said. "There is no way to block the Killing Curse, unless you are able to produce someone willing to die for me."

"There you go," said the Doctor, after a fraction of a second's hesitation. "If he's all right with it, why can't you be?"

"Because it's not fair," she said in a small voice, clearly aware that her argument was feeble, if touching. "He saved Harry Potter so many times and worked his entire life to make up for one stupid mistake when he was just a kid. It's rubbish that he's got to die."

"Yeah, it is," said the Doctor, quietly.

She looked up at him quizzically.

"Don't look at me like that, Martha Jones," he said sternly. "I've been a Slytherin apologist since the moment Snape here rolled up his sleeve to show that idiot Fudge his Dark Mark." He turned to Severus. "Look, we don't really have to start worrying about this unless there's been a recent break-in at Gringott's. And I don't mean the Philosopher's Stone, I mean something very recent."

Severus was relieved to return to a topic that was not his inevitable death, though he was determined not to show it. "There hasn't. What happens then?"

At this point, his Dark Mark began to burn, and he clutched it reflexively.

"Is that your…" Martha's question trailed off meaningfully.

At this point, the door to Severus's office burst open to reveal a wild-eyed Amycus Carrow, also squeezing his forearm. "Snape!" he wheezed, clearly out of breath from running. "You've got to do something! It's all over! I don't know how to make the students shut their stinking mouths!"

"Surely even you can cast a Silencing Charm," snarled Snape, furious at being interrupted.

"It's the blasted owls," whined Amycus. "They done found out about it from their ruddy parents."

"Found out what?" asked the Doctor.

Amycus glanced at him. "The robbery from Gringott's, of course. Bella's family vault it was, and Potter and his sidekicks the ones responsible. The Dark Lord'll be-" here Amycus's lumpy face froze. He glanced over at his interrogator and stared open-mouthed. "Merlin on a fucking Firebolt," he exclaimed. "Barty?"

"The same," said the Doctor.

"Lillith and Morrigan!" he exclaimed, a lopsided grin spreading over his hideous face. "If you're not a sight for sore eyes! Come on, then! Let's see if you're as good as you used to be. I've got a whole room full of the blighters in need of a bit of discipline."

"I'm afraid the Dark Lord has other plans for me and Mister Crouch," said Severus in his most supercilious manner.

"Right, of course," said Amycus. "Oh, and Snape, I was wondering if I could take over the Squib's equipment. My whip's got all frayed, and his manacles are much higher quality."

"Do as you see fit," said Severus, who hoped his distaste would come across as impatience.

Amycus gave a slight incline of his head and left.

"Was that a Death Eater?" asked Martha incredulously.

"Yeah, it was," said the Doctor.

"Why the hell are there Death Eaters at Hogwarts?"

"Look, Martha, there's a lot I need to tell you, but really, it's taking a back seat to what I need to tell Severus. As in, NOW. I know it won't make a lot of sense to you, but please trust that I know what I'm doing and don't interrupt."

"I promise. And I don't care if it spoils the last book for me. I want to help."

"Right. So this is what we're going to do."

~*~*~*~*~*~*~*~*~

"For the last time, I have no bloody idea!" yelled Ron Weasley.

"Well, we can't do nothing!" shouted Hermione Granger. "Unless you can come up with a better idea, I'm going to the library, and you can just run off and leave us again, Ron. It's obvious you're not good at much else."

She ran off down the hallway and Ron sagged to the floor, weeping silently at first, and then in earnest.

"Wow," said Martha. "Harsh."

"She's not entirely wrong," said the Doctor, "but yeah. Harsh."

Ron jumped up, his wand at the ready. "Who the hell-" he stopped short, staring at the Doctor, aghast.

The Doctor sighed. "Not him. Just look like him. Now, you're trying to find a way to destroy that cup, right?"

Ron's jaw dropped. "How did you-"

"I've got it," said Martha.

"You do?" asked Ron hopefully.

She turned to face the Doctor. "When you have to make yourself all over again, you can't just will new matter into being, right? So what if souls, or whatever the essence of someone's life is called, can transcend time and space? What's left of Barty hangs in the ether and you sort of suck it up when you need a new body."

The Doctor considered. "You might be on to something, Martha Jones."

"Erm, what's all this got to do with destroying the Hufflepuff cup?"

"Come ON!" exclaimed Martha. "I figured this out and I haven't even read the book yet. How were the other Horcuxes destroyed? And I don't just mean the ones you lot have destroyed."

"Well, Dumbledore destroyed the ring," said Ron, thinking so hard Martha expected his hair to catch fire.

"And before that?" prompted the Doctor. "You know, the one that almost killed your sister?"

"The diary!" said Ron. "Harry stuck a Basilisk fang through it!"

"Exactly," said the Doctor, grinning. "Now, where are you going to find a Basilisk fang?"

Ron's face fell. "Snape's potions stores?"

"The Chamber of Secrets!" exclaimed Martha. "Honestly, it's like you weren't even there!"

"Well, I wasn't entirely," began Ron.

"Never mind," said the Doctor, hastily. "Just do what you need to do to get in there."

"But I can't speak Parseltongue," wailed Ron.

The Doctor pulled his sonic screwdriver from his pocket. "Blimey!" he exclaimed. "Just go and find Hermione and take her to Myrtle's bathroom. I'll leave the chamber door open for you!"

Ron gave the Doctor a look of pathetic gratefulness and ran off down the hall.

Martha gave the Doctor a knowing smile. "Did that change anything?"

"Naw, except that people who value consistency might be a bit annoyed. Parseltongue isn't something you can fake, you know."

"Ron figuring out the cup won't have any repercussions, will it?"

"Well," began the Doctor. "That is- well- naaah. There has to be something else she sees in him."

"Who?"

"Nothing. Now, go!"

~*~*~*~*~*~*~*~*~

"Shit," said Martha.

There were a lot more potions bottles than she expected there to be, all of them labeled in fastidious but tiny penmanship.

"What might you be looking for, young lady?"

Martha spun around to find a fat man in a green dressing gown looking at her curiously. Her gaze took in the golden whiskers and sumptuous fabric, and she concluded that this must be Horace Slughorn.

"A bezoar," said Martha. "Or maybe not. Something that can stop a deadly snakebite."

"Now, now" he said condescendingly. "The only poisonous snake in Britain is the adder and its venom isn't strong enough to kill a human."

"This isn't a natural snake," said Martha sharply. "It's a Horcrux. You know what those are."

Slughorn's avuncular charm evaporated. "What did you say?" he nearly whispered, clutching his heart.

"A giant snake, enhanced by the darkest magic, is set upon you and ordered to kill." said Martha, who was enjoying her turn as prognosticator. "How would you stop it?"

Slughorn's abject terror subsided slightly when presented with a potions question. "I'd-" he began, but broke off to clear his throat. He looked at Martha shrewdly. "I do not take political positions lightly," he said. "Nor do I acknowledge any sort of conclusion that may be drawn from the fact that you are looking for a way to defeat a Horcrux. And as such, I will not tell you what I would do in such a case."

"Oh," said Martha, deflating slightly.

An unexpected fire lit Horace Slughorn's eye. "But I will be happy to demonstrate. Be so good as to bottle some Blood Replenishing Potion while I start on this. It's the cauldron in the corner. That's a good girl."

~*~*~*~*~*~*~*~*~

"Barty!" gasped Narcissa, rising from the fallen tree where she sat watching the gathering troops. "But how-?"

"The Dementors," rasped the Doctor. "They feed, but they cannot actually destroy."

She clasped him to her breast. "Dear boy, we thought you were dead."

"Never," said the Doctor. "My father, you know that he died?"

"By your hand," said Narcissa.

"And that was the beautiful thing," said the Doctor, allowing his eyes to widen to a disturbing degree. "He was dying for me, despite the fact that I killed him. I was protected in ways that the Dementors cannot have imagined."

He could tell that Narcissa was intrigued, even though her face remained serene. "That's an incredible story," she said diplomatically.

"The bonds of family transcend all things," said the Doctor, allowing his twitching, manic persona to drop momentarily. "Even the Dark Lord's plans." He feigned a look of panic. "You won't tell him you saw me?" he pleaded. "I don't want him to know I'm here, not when my father died to give my soul a chance to redeem itself."

Narcissa was obviously troubled. A frown line marred her otherwise flawless brow. "I won't say anything," she said at last.

"Thank you," breathed the Doctor. "Nimue protect you and Lucius and Draco."

Narcissa inclined her head slightly and returned to the group of Death Eaters surrounding the Dark Lord, and the Doctor ran back towards the castle, grinning in an un-Barty-like way.

~*~*~*~*~*~*~*~*~

The battle raged below. Martha was picking her way along the corridor towards the headmaster's office, doing her best to avoid flying curses and animated suits of armour. As she finally located a staircase to the seventh floor, there was a loud explosion.

"LOOK OUT!" Martha screamed, seizing the arm of the nearest person to her and dragging him out of the way of the wall whose pieces seemed to hang in midair before crashing down where they had been.

The young man with ginger hair landed next to her. "Thanks, Angelina-" he began to say, hardly looking at her, and then he looked around him wild-eyed. "Fred," he whispered. He leapt to his feet and began searching through the wreckage.

Martha lurched to her feet, ears still ringing, and began to climb the stairs, barely registering the heart-rending screams behind her.

~*~*~*~*~*~*~*~*~

The Doctor was pacing the circumference of Severus's carpet when the door burst open to admit Martha. She was covered in dirt and dust and her eyes were red, but her face was resolute.

"I've done it," she said, wiping her nose. "I've got the antidote to Snape and Slughorn knows what to do."

"Here, now," said the Doctor, embracing her. "What's got you all upset?"

"I just saw Fred Weasley die," she said, bursting into tears.

The Doctor held her. "There, there," he said. "I cried for him, too. At least George made it."

"He wouldn't have if I hadn't grabbed him out of the way," she sniffed. "I'd have grabbed both of them, but it happened so fast, and I didn't see him. He might not be dead if I'd-"

"Stop that," said the Doctor, looking into her eyes. "You are not responsible. Whoever cast that hex is. You, my dear Martha Jones, are a genius."

She scowled at him. "Don't you get it? People are dying and we can't do anything to stop it'!"

The Doctor pressed his lips to her forehead and held her head against his chest. "Martha, you've brought about one of the few bright spots in the end of that bloody awful book. Two, if you count Snape surviving, which happens between the lines. I just wish-"

"What?" asked Martha, warmed by his tenderness but still very much affected by the chaos and mayhem.

"I just wish we could have got here sooner and done something about all the bloody camping. And never mind what that means, you'll understand in a year or so. Now, we need to go. Harry is going to need this room soon."

"Harry Potter?" said Martha, interested despite her exhaustion.

"Yes," said the Doctor, with a sad smile. "And we're not to see him. You know the books are told from his perspective. We don't want the last book to be marred by a sudden mention of a police box, or worse, from seeing Barty Crouch returned from the dead."

"I think it'd be brilliant to be in a Harry Potter book."

"Poor Jo would get sued," said the Doctor, not entirely without regret. "Don't worry. There are enough clever readers out there. Someone will eventually put two and two together about what we did here."

"You think so?" asked Martha doubtfully.

"I'd bet on it," said the Doctor, holding open the door to the TARDIS. "Let's go."

~*~*~*~*~*~*~*~*~

Severus opened his eyes to find himself in what appeared to be a Muggle hospital. He looked around and discovered that he was hooked up to a number of machines, and several tubes were attached to his arm. A man in a trench coat was sitting in a chair next to his bed.

"Welcome back," he said, with an all-too-charming grin. Severus was strongly reminded of Gilderoy Lockhart.

"Where am I?" His throat was dry, but none the worse for wear, despite that brute of a snake's attempts.

"Cardiff."

Severus narrowed his eyes at him. "Why Cardiff?"

The man's grin broadened. "Why not?"

Severus made a reflexive grab for his wand, but it wasn't there.

"I took the liberty of taking this for safe keeping," said the man, holding up Severus's wand. "Firstly because the Muggles wouldn't know what it was, and secondly because I wanted to make sure you wouldn't curse me before I could offer you a job."

"Who are you?"

"Captain Jack Harkness, Torchwood. You come very highly recommended."

"By whom?" snorted Severus.

"A mutual friend. Now, I know you just woke up, so let me give you some time to consider-"

"I'll do it," interrupted Severus.

Jack raised an eyebrow at him. "Don't you want to know what the job is, first?"

Severus looked at him down his nose. "It's not teaching, is it?"

Jack snickered. "No."

"Then I'll start as soon as I'm released."

"All right" said Jack, handing Severus his wand. "I must say, from what I'd been led to believe, I thought you'd be a lot harder to convince."

"For nearly twenty years, I have been at the beck and call of one master or another. I haven't slept for longer than five hours on any given night, I haven't had sex in years, and I've had pumpkin juice at every meal. I'm sure I shall regret this decision at some point, but I will always remember it as the first one I made in my new life."

"You haven't had sex in years?" asked Jack, looking far too interested.

"I was wrong, I'm already regretting the decision," grumbled Severus. "Now go away."

Jack tossed a mobile phone on the bed. "Call me when they give you a clean bill of health. For the job," he clarified.

Severus nodded, and Jack turned to go."The rest can, of course, be negotiated at a later point," he said over his shoulder, just as the door was closing.

Severus lay back in his bed, listening to the machines beep, and noticing that his bed was equipped with a remote control for the television. 

He sighed happily.

All was well.

~*~*~*~*~*~*~*~*~

The End

~*~*~*~*~*~*~*~*~

**Author's Note:**

> Enormous thanks to Mr. 42, my intrepid, beloved beta-reader and to morethansirius for giving me an excuse to dip my toe in DW fandom!


End file.
